Idiopathic First Bite Syndrome Associated With Diabetic Autonomic Neuropathy.

First bite syndrome (FBS) is a rare pain disorder characterized by sharp parotid pain triggered by the first bite of each meal and diminishing with continued mastication. It is most often reported as a complication of parapharyngeal or sympathetic chain surgery, with an incidence of approximately 6% to 10% in surgical series. Idiopathic cases, in which no prior surgery or local cause is identified, are exceedingly uncommon, with fewer than 10 described in the literature. Several of these involved patients with diabetes mellitus, suggesting a possible role for autonomic neuropathy. We present a 63-year-old woman with poorly controlled type 2 diabetes who developed parotid pain consistent with idiopathic FBS, without any history of head or neck surgery. Imaging was normal, and neurologic testing confirmed diabetic autonomic neuropathy. With reinitiation of insulin and improved glycemic control, symptoms resolved in parallel with hemoglobin A1c reduction. This case highlights a presentation clinically compatible with idiopathic FBS secondary to diabetic autonomic neuropathy and underscores the importance of recognizing systemic contributors to parotid pain, which may resolve with metabolic optimization.